Etruscan Origins of Roman Numerals

Date: 12/07/2003 at 19:27:27
From: Matthew
Subject: Roman Numeral Origin

I have been teaching my second graders Roman Numerals.  When we got to
L for fifty, they wanted to know what the L stood for.  Is there some
Latin word that means 'fifty' that begins with L? 

And while you're at it, how about V, X, L, C, and D?

Date: 12/08/2003 at 08:54:45
From: Doctor Peterson
Subject: Re: Roman Numeral Origin

Hi, Matthew.

The origin of the symbols is not quite clear; it is believed that they 
come from earlier Etruscan numerals, and that even the "obvious" C and 
M don't really come from centum and mille (though they may be 
influenced by the words), but from other symbols.

Here is one page (a link listed in our FAQ on the topic) that touches 
on the question:

  Roman Numerals: History and Use
    http://www.wilkiecollins.demon.co.uk/roman/intro.htm 

  The history of Roman numerals is not well documented and written
  accounts are contradictory. It is likely that counting began on
  the fingers and that is why we count in tens. A single stroke I
  represents one finger, five or a handful could possibly be
  represented by V and the X may have been used because if you
  stretch out two handfuls of fingers and place them close the two
  little fingers cross in an X. Alternatively, an X is like two Vs,
  one upside down. Although the Latin for 100 is centum and for
  1000 is mille, scholars generally do not think that C is 100 and
  M is 1000 because they are the initial letters of centum and
  mille. The use of D could be a representation of a C with a
  vertical line through it representing half. My own views is that
  M arose out of the use of () symbols to multiply by 1000. This
  theory is supported by the use of ( I ) for 1000 and I ) for
  500. These could easily become corrupted or abbreviated into M
  or D which they resemble.

This page shows how C, L, M, and D developed (see the picture there):

  The Latin Alphabet
    http://www.du.edu/~etuttle/classics/latalph.htm 

  Some of the old letters dropped from the Greek alphabet were
  retained as numbers. The same thing happened in Latin with a few
  of the Etruscan letters that did not correspond to Latin sounds,
  as shown at the left. The number symbols evolved into the normal
  letters C, L, M and D in the course of time, though the symbol
  for 1000 was adapted for expressing larger powers of 10 by
  adding more forward and backward C's. It is said that the L came
  from the Etruscan chi, but it could just as well have been half
  of the C symbol, as the D comes from half of the M. All these
  number symbols represented abacus counter columns, together with
  the I, V and X, so that I, C and M need be repeated no more than
  four times, V, L, and D no more than twice, in specifying a
  number. The representation of large numbers and of fractions in
  Roman numerals or Greek numerals is a complicated subject. Roman
  numerals were used for business, Greek numerals for science.

These pages show the Etruscan alphabet and numerals, which I can't 
copy here:

  Etruscan Language
    http://www.mysteriousetruscans.com/language.html 

  Etruscan Alphabet
    http://www.omniglot.com/writing/etruscan.htm 

If you have any further questions, feel free to write back.

- Doctor Peterson, The Math Forum
  http://mathforum.org/dr.math/